1. Field of the Invention
The present invention relates to a method of slimming a resist pattern used for a semiconductor process, a method of manufacturing a semiconductor device using the method of slimming, and a resist coating and developing system.
2. Description of the Related Art
With the miniaturization of semiconductor devices, it has been difficult to sufficiently secure an exposure contrast of 1:1 for a dense pattern using optical exposure technology only. To overcome this problem, methods of 1) combining a new layer with a pattern to form a dense pattern and 2) forming a pattern in a two-stage process to form a dense pattern have recently been considered.
It is important how thinly the line width of a pattern can be formed in any of the above-described methods.
Patent documents 1-3 below, for example, disclose techniques of forming a resist pattern with a thin line width.    Patent document 1: Japanese Unexamined Patent Publication No. 2001-281886;    Patent document 2: Japanese Unexamined Patent Publication No. 2002-299202; and    Patent document 3: Japanese Unexamined Patent Publication No. 2003-215814.
In Patent document 1, a resist pattern is formed using chemically amplified resist. An acid layer is coated on the resist pattern and the surface portion of the resist pattern is changed to be alkali soluble. By removing the alkali soluble surface portion, the line width of the resist pattern may be further decreased, compared to the original line width.
In Patent document 2, a resist pattern is formed using chemically amplified resist. A reforming member is coated on the resist pattern to be dispersed in the resist pattern. Then, the reforming member and a portion of the resist pattern that becomes soluble as the reforming member is dispersed are removed. Thus, the line width of the resist pattern may be further decreased, compared to the original line width.
In Patent document 3, after a resist pattern is formed, a pattern thin-wall material (a reducing material) is coated on the resist pattern so that a pattern mixing layer is formed on the surface of the resist pattern. Then, the pattern thin-wall material and the pattern mixing layer are removed so that the line width of the resist pattern may be further decreased, compared to the original line width.
In Patent documents 1-3, by solubilizing the surface of the resist pattern, the line width of the resist pattern may be further decreased, compared to the original line width (hereinafter, in the specification, referred to as slimming).
However, demand for pattern miniaturization has been continuously high and accordingly the line width needed for the pattern has decreased. Also, the sensitivity of the resist itself has increased to form a finer pattern. When a process to solubilize the surface of the resist pattern is added in order to slim the resist pattern, the pattern is likely to be easily collapsed due to the above-described various factors.